Optical imaging lens

Abstract

The present invention provides an optical imaging lens. The optical imaging lens comprises eight lens elements positioned in an order from an object side to an image side. Through controlling convex or concave shape of surfaces of the lens elements and satisfying at least one inequality, the optical imaging lens may shorten system length with a good imaging quality.

What is claimed is: 
     
       1. An optical imaging lens, comprising a first element, a second element, a third element, a fourth element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element sequentially from an object side to an image side along an optical axis, each of the first, second, third, fourth, fifth, sixth, seventh and eighth lens element having an object-side surface facing toward the object side and allowing imaging rays to pass through and an image-side surface facing toward the image side and allowing the imaging rays to pass through, wherein:
 a periphery region of the image-side surface of the second lens element is concave; 
 an optical axis region of the image-side surface of the third lens element is concave or a periphery region of the object-side surface of the fourth lens element is concave; 
 an optical axis region of the image-side surface of the fourth lens element is convex; 
 a periphery region of the object-side surface of the fifth lens element is concave; 
 a periphery region of the object-side surface of the seventh lens element is concave; 
 lens elements of the optical imaging lens consist of the eight lens elements described above; and 
 a distance from the object-side surface of the first lens element to an image plane along the optical axis is represented by TTL, an image height of the optical imaging lens is represented by ImgH, a distance from the object-side surface of the first lens element to the image-side surface of the eighth lens element along the optical axis is represented by TL, a f-number of the optical imaging lens is represented by Fno, a distance from the image-side surface of the fourth lens element to the object-side surface of the seventh lens element along the optical axis is represented by D42t71, and the optical imaging lens satisfies the inequalities:
   TTL/ImgH≤1.500;
 
   TL*Fno/ImgH≤2.500; and
 
   TTL/ D 42 t 71≤4.500.
 
 
 
     
     
       2. The optical imaging lens according to  claim 1 , wherein an abbe number of the third lens element is represented by V3, and V3 satisfies the inequality:
   49.000≤ V 3≤60.000.
 
 
     
     
       3. The optical imaging lens according to  claim 1 , wherein a distance from the object-side surface of the seventh lens element to the image plane along the optical axis is represented by TTL7I, and TTL7I and D42t71 satisfies the inequality:
   TTL7 I/D 42 t 71≤2.000.
 
 
     
     
       4. The optical imaging lens according to  claim 1 , wherein a sum of the five air gaps from the third lens element to the eighth lens element along the optical axis is represented by AAG38, a thickness of the third lens element along the optical axis is represented by T3, and AAG38 and T3 satisfy the inequality:
   AAG38 /T 3≤4.000.
 
 
     
     
       5. The optical imaging lens according to  claim 1 , wherein a sum of the thicknesses of four lens elements from the fourth to sixth lens elements along the optical axis is represented by ALT46, a distance from the image-side surface of the seventh lens element to the object-side surface of the eighth lens element along the optical axis is represented by G78, a distance from the image-side surface of the first lens element to the object-side surface of the second lens element along the optical axis is represented by G12, a thickness of the third lens element along the optical axis is represented by T3, and ALT46, G78, G12 and T3 satisfy the inequality:
   (ALT46+ G 78)/( G 12+ T 3)≤2.100.
 
 
     
     
       6. The optical imaging lens according to  claim 1 , wherein a sum of the thicknesses of eight lens elements from the first element to the eighth element along the optical axis is represented by ALT, a thickness of the third lens element along the optical axis is represented by T3, a thickness of the seventh lens element along the optical axis is represented by T7, and ALT, T3 and T7 satisfy the inequality:
   ALT/( T 3+ T 7)≤3.900.
 
 
     
     
       7. The optical imaging lens according to  claim 1 , wherein an effective focal length of the optical imaging lens is represented by EFL, and EFL and ImgH satisfy the inequality:
   EFL/ImgH≤1.250.
 
 
     
     
       8. The optical imaging lens according to  claim 1 , wherein:
 a periphery region of the image-side surface of the third lens element is convex; 
 the periphery region of the object-side surface of the fourth lens element is concave; and 
 the fifth lens element has negative refracting power, and a periphery region of the image-side surface of the fifth lens element is convex. 
 
     
     
       9. The optical imaging lens according to  claim 1 , wherein an abbe number of the sixth lens element is represented by V6, and V6 satisfies the inequality:
   49.000 ≤V 6≤60.000.
 
 
     
     
       10. The optical imaging lens according to  claim 1 , wherein a distance from the object-side surface of the seventh lens element to the image plane along the optical axis is represented by TTL7I, and TTL7I and D42t71 satisfy the inequality:
   TTL7 I/D 42 t 71≤2.000.
 
 
     
     
       11. The optical imaging lens according to  claim 1 , wherein a sum of the five air gaps from the third lens element to the seventh lens element along the optical axis is represented by AAG37, a thickness of the seventh lens element along the optical axis is represented by T7, and AAG37 and T7 satisfy the inequality:
   AAG37 /T 7≤3.800.
 
 
     
     
       12. The optical imaging lens according to  claim 1 , wherein a sum of the thicknesses of four lens elements from the fourth to sixth lens elements along the optical axis is represented by ALT46, a thickness of the second lens element along the optical axis is represented by T2, a distance from the image-side surface of the first lens element to the object-side surface of the second lens element along the optical axis is represented by G12, a thickness of the seventh lens element along the optical axis is represented by T7, and ALT46, T2, G12 and T7 satisfy the inequality:
   (ALT46+ T 2)/( G 12+ T 7)≤2.700.
 
 
     
     
       13. The optical imaging lens according to  claim 1 , wherein a sum of the thicknesses of eight lens elements from the first element to the eighth element along the optical axis is represented by ALT, a thickness of the third lens element along the optical axis is represented by T3, a thickness of the eighth lens element along the optical axis is represented by T8, and ALT, T3 and T8 satisfy the inequality:
   ALT/( T 3+ T 8)≤3.600.
 
 
     
     
       14. The optical imaging lens according to  claim 1 , wherein a distance from the object-side surface of the first lens element to the object-side surface of the seventh lens element along the optical axis is represented by D11t71, a distance from the object-side surface of the seventh lens element to the image-side surface of the eighth lens element along the optical axis is represented by D71t82, and D11t71 and D71t82 satisfy the inequality:
     D 11 t 71/ D 71 t 82≤3.500.
 
 
     
     
       15. The optical imaging lens according to  claim 1 , wherein:
 a periphery region of the image-side surface of the third lens element is convex; and 
 an optical axis region of the image-side surface of the fifth lens element is concave. 
 
     
     
       16. The optical imaging lens according to  claim 1 , wherein an abbe number of the first lens element is represented by V1, an abbe number of the second lens element is represented by V2, an abbe number of the third lens element is represented by V3, an abbe number of the fourth lens element is represented by V4, an abbe number of the fifth lens element is represented by V5, an abbe number of the sixth lens element is represented by V6, an abbe number of the seventh lens element is represented by V7, and V1, V2, V3, V4, V5, V6 and V7 satisfy the inequality:
     V 1+ V 2+ V 3+ V 4+ V 5+ V 6+ V 7≤290.000.
 
 
     
     
       17. The optical imaging lens according to  claim 1 , wherein a distance from the object-side surface of the seventh lens element to the image-side surface of the eighth lens element along the optical axis is represented by D71t82, and TTL and D71t82 satisfy the inequality:
   TTL/ D 71 t 82≤5.500.
 
 
     
     
       18. The optical imaging lens according to  claim 1 , wherein a sum of the seven air gaps from the first lens element to the eighth lens element along the optical axis is represented by AAG, a distance from the image-side surface of the first lens element to the object-side surface of the second lens element along the optical axis is represented by G12, a distance from the image-side surface of the second lens element to the object-side surface of the third lens element along the optical axis is represented by G23, and AAG, G12 and G23 satisfy the inequality:
   AAG/( G 12+ G 23)≤6.400.
 
 
     
     
       19. The optical imaging lens according to  claim 1 , wherein a sum of the thicknesses of four lens elements from the fourth to sixth lens elements along the optical axis is represented by ALT46, a thickness of the first lens element along the optical axis is represented by T1, a distance from the image-side surface of the first lens element to the object-side surface of the second lens element along the optical axis is represented by G12, a thickness of the eighth lens element along the optical axis is represented by T8, and ALT46, T1, G12 and T8 satisfy the inequality:
   (ALT46+ T 1)/( G 12+ T 8)≤2.600.